BEIRUT — Syria’s military launched a new assault Tuesday aimed at reasserting its authority in the east of the country, battling U.S.-backed opposition fighters in the remote desert near the borders with Iraq and Jordan. The government forces’ ultimate goal is to insert itself in the fight against the Islamic State group in the oil-rich region.

The government offensive came as the Trump administration announced it would arm Syria’s Kurdish fighters “as necessary” to recapture the key Islamic State stronghold of Raqqa. The decision is meant to accelerate the Raqqa operation, but is strongly opposed by key NATO ally Turkey, which sees the Syrian Kurdish group, known as the YPG, as an extension of the Kurdish insurgency raging in its southeast.

The decision is likely to complicate the way going forward, as the U.S. has deployed additional troops to act as a buffer between Syria’s Kurds and Turkey along the country’s northern border.

Dana W. White, the Pentagon’s chief spokeswoman, said in a written statement that President Donald Trump’s authorization of arms to the Syrian Kurds gives the Pentagon the go-ahead to “equip Kurdish elements of the Syrian Democratic Forces as necessary to ensure a clear victory over ISIS” in Raqqa.